I can only comment on a small subset of the whole issue. As far as warranty issues (or the general aftersales process) are concerned, according to the legislation in my country you wouldn't be responsible for features you don't promise. While "taking a screenshot" might seem the most basic thing for those who are used to it, it will not be a warranty issue as long as there's no text on the box or in the manual that states "easily take screenshots by using...". (IIRC, the earlier versions of SFOS didn't have a built-in way of taking screenshots either.) Same for battery life. Some people might expect more, but if it's given in the specs, then it's not an issue.

I can't comment on things like stability of the USB port, simply because I don't have any such structural problems on my 2 Jolla tablets. Maybe it isn't as bad at all.

As for risk management: I would guess that many potential customers know SailfishOS, its strengths and weaknesses, very well. They will be forgiving when it comes to software issues.